Third MMR dose likely stopped 2009-2010 New York mumps outbreak
Guidelines in the United States call for children to receive two doses of the vaccine, one at approximately one year of age and a second at between 4-6 years. The New York outbreak, however, showed that mumps is capable of spreading in close-knit communities even when children are properly vaccinated, according to NBC News.
The CDC study said that the outbreak occurred among members of an Orthodox Jewish community at a religious camp in the Catskill Mountains. The illness was likely spread because of a method of schooling, called chavrusas, that involves close contact between study partners.
Over five months beginning in September 2009, nearly 400 people were infected with the mumps in one Orange County village. The illness was concentrated among those attending three local schools.
"Most of these outbreaks of mumps occur in very crowded settings," Dr. Preeta Kutty, a CDC researcher who worked on the report, said, NBC News reports. "Although the majority of the children (who got mumps) had received two doses of the vaccine, the intensity of exposure overcame that protection."
When outbreak-control efforts such as isolation failed, health officials began offering students a third dose of the MMR vaccine as an option. Within weeks, the rate of mumps attacks fell dramatically. The report said that there is no definitive proof that the third dose was responsible for the end of the outbreak, but that booster shots could be used as another tool if other strategies fail.
"The vaccine is so safe and the evidence is very reasonable now," Dr. Saad Omer from the Emory Vaccine Center said, Reuters Health reports. "I think (a third vaccine) should be on the list of first-line options for decent-sized outbreaks."